The present invention relates to a circuit substrate and the technology for providing the circuit substrate, and more particularly to a circuit substrate, which is suitable especially when organic binder is used as a binder and base metal conductive material such as copper is used as conducting material, a method of manufacturing thereof, and glass and ceramic composition for manufacturing the circuit substrate.
Conventionally, for multilayer circuit substrate on which silicon semiconductor integrated circuit elements are mounted, alumina (Al.sub.2 O.sub.3) has been used as insulating material, molybdenum (Mo) and tungsten (W), which have high melting point and are possible to be co-sintered with alumina, has been used as conducting material. However, because the thermal expansion coefficient of alumina is as high as about 7.times.10.sup.-6 /.degree. C., when silicon semiconductor elements are mounted directly on an alumina substrate, the conductive connection is subjected to the serious stress, and the connection become unreliable. In addition, because of high relative dielectric constant of alumina as high as about 10, the signal transmission is not sufficiently fast as expected for high performance multilayer circuit substrate. Moreover, the resistance of above-mentioned metals are relatively high. To solve the problems, in Japanese Patent Provisional Publication Heisei-2-49550 (1990), a multilayer ceramic circuit substrate and manufacture thereof having copper conducting layer and glass ceramic layer containing a mixture consisting of 20% or more and less than 50% by weight of alumina, 10% or more and less than 60% by weight of quartz glass, and 20% or more and less than 40% by weight of amorphous glass or crystallized glass, and using a binder containing thermal depolymerization type resin.